more rails partials on the same page - ruby-on-rails

Question

I have a rails app. I'm displaying more partials (user, task, conversation, message) from different classes on the users/:id/show page. I set all the instance variables (for other classes as well) in the users.controller's def show action.
It seems to be a bit heavy, so is there a better approach than this? (I'm using #task and #message for the AJAX calls.)
def show
#user = User.find(params[:id])
if Task.between(current_user.id, #user.id).present?
#tasks = Task.uncompleted.between(current_user.id, #user.id).order("created_at DESC").includes(:assigner).paginate(page: params[:page], per_page: 12)
#task = Task.new
if Conversation.between(current_user.id, #user.id).present?
#conversation = Conversation.between(current_user.id, #user.id).first
#messages = #conversation.messages.includes(:user)
#message = Message.new
respond_to do |format|
format.html
format.js { render :template => "tasks/update.js.erb", :template => "tasks/destroy.js.erb", layout: false }
end
end
else
redirect_to user_profile_path(#user)
end
end
UPDATED:
users/show:
<%if #conversation%>
<%= render 'conversations/show' %>
<% end %>
<tbody class="newtaskinsert2">
<%= render partial: "tasks/task_between", collection: #tasks, as: :task %>
</tbody>
conversations/_show:
<div class="chatboxcontent">
<% if #messages.any? %>
<%= render #messages %>
<% end %>
</div>
<div class="chatboxinput">
<%= form_for([#conversation, #message], :remote => true, :html => {id: "conversation_form_#{#conversation.id}"}) do |f| %>
<%= f.text_area :body, class: "chatboxtextarea", "data-cid" => #conversation.id %>
<% end %>
<%= form_for([#conversation, #message], html: {class: "refile_form"}, remote: true) do |form| %>
<span class="btn btn-success btn-sm btn-file">Choose file
<%= form.attachment_field :message_attachment, direct: true, presigned: true, class: "choosefile" %></span>
<%= form.submit "Send File", class: "btn btn-primary btn-sm btn-submit-refile", style:"display:none"%>
<% end %>
<span id="progresspercent"></span>
</div>

Answer 1

You can keep only #user instance variable in the controller, and in partials use: #user.tasks instead of #tasks, #user.tasks.new instead of #task etc. Note also, that you can pass parameters to partials (3.4.4 Passing Local Variables)
For sample:
<%= render partial: "your_partial", locals: {tasks: #user.tasks} %>
Update:
With your way (call methods from class instead of objects) you can do something like it:
def show
#user = User.find(params[:id])
if Task.between(current_user.id, #user.id).present?
# #user.tasks.where(another_user_field_name: current_user).present? - looks more like Rails way
#tasks = Task.uncompleted.between(current_user.id, #user.id).order("created_at DESC").includes(:assigner).paginate(page: params[:page], per_page: 12)
#conversation = Conversation.between(current_user.id, #user.id).first
if #conversation
respond_to do |format|
format.html
format.js { render :template => "tasks/update.js.erb", :template => "tasks/destroy.js.erb", layout: false }
end
end
# Do not forget that if #conversation is not exists this code render views by default way
else
redirect_to user_profile_path(#user)
end
end
<%= render 'conversations/show' %>
<tbody class="newtaskinsert2">
<%= render partial: "tasks/task_between"%>
</tbody>
<%if #conversation%>
<div class="chatboxcontent">
<%= render '_your_messages_partial', locals: {messages: #conversation.messages.includes(:user)}%>
</div>
<div class="chatboxinput">
<%= form_for([#conversation, #conversation.messages.new], :remote => true, :html => {id: "conversation_form_#{#conversation.id}"}) do |f| %>
<%= f.text_area :body, class: "chatboxtextarea", "data-cid" => #conversation.id %>
<% end %>
<%= form_for([#conversation, #conversation.messages.new], html: {class: "refile_form"}, remote: true) do |form| %>
<span class="btn btn-success btn-sm btn-file">Choose file
<%= form.attachment_field :message_attachment, direct: true, presigned: true, class: "choosefile" %></span>
<%= form.submit "Send File", class: "btn btn-primary btn-sm btn-submit-refile", style:"display:none"%>
<% end %>
<span id="progresspercent"></span>
</div>
<% end %>
You can make this code more shorter in case of using relations (#user.conversations instead of Conversation.between... etc)

Answer 2

I would suggest to use caching techniques for your views:
http://edgeguides.rubyonrails.org/caching_with_rails.html#fragment-caching
http://edgeguides.rubyonrails.org/caching_with_rails.html#russian-doll-caching
In the extreme scenario where performance is still an issue for you, I would recommend to start denormalising the partials until you re happy with the performance.